The present invention relates to a resin molding machine, more precisely relates to a resin molding machine, in which a work is clamped and molded with resin in a molding die.
A transfer molding machine, which molds resin mold sections (package sections) of semiconductor devices with resin, has been known as an example of resin molding machines. In the transfer molding machine, works, e.g., mere substrates, plastic boards on which semiconductor chips are mounted, lead frames on which semiconductor chips are mounted, are set in a molding die having cavities and clamped by the molding die. Resin supplied in a pot is pressurized by a plunger so as to send the resin to the cavities via resin paths (runners and gates). By filling the cavity, the mold sections of the work are molded with the resin.
For example, CSP (Chip Size Package) type semiconductor devices are manufactured by simultaneously molding semiconductor chips, which are metrically arranged on one side face of a work, with resin. Then, the molded chips on the work are respectively cut by a dicing machine. The cut pieces become the semiconductor devices.
The molding die includes an upper die and a lower die. To fill the cavities, in which the semiconductor chips are accommodated, with the resin, runners and gates for introducing the resin are formed on a substrate of the work. Therefore, special pretreatments of the substrate, e.g., gold plating for degating useless resin, are required, so that number of manufacturing steps must be increased. Namely, manufacturing efficiency is lowered, and manufacturing costs must be increased.
In the case of molding the one side of the substrate of the work, resin fins are extended from edges of the substrate, so that maintenance of the molding die is required.
To resin-mold prescribed areas of the substrate without touching the resin with other areas, a method of resin molding, in which a cavity plate having cavity holes is piled on the substrate (a printed circuit board), was proposed (see Japanese Patent Gazette No. 61-46049).
However, in the method disclosed in the Japanese Patent Gazette, the circuit board and the cavity plate, whose size is almost equal to that of the circuit board, are merely piled by respectively piercing pins of a molding die. The gazette does not disclose how to carry the cavity plate and the circuit board into the molding die, how to carry out the molded circuit board therefrom, how to remove useless resin from the molded products and how to separate the cavity plate from the molded circuit board. Further, runners and gates are formed on a clamping face of the molding die, so the molding die must be frequently cleaned and maintained. Therefore, manufacturing efficiency of the resin molding machine must be lowered.